function [f, acceleration_fft_abs] = my_fft(acceleration)

N = 256;
acceleration_fft = fft(acceleration, N);
% acceleration_fft = fft(acceleration);
% N = length(acceleration); % number of sampled points

fs = 100; % sample frequency = 1 / 0.01 = 100 Hz
n = 0 : N-1;
f = n * fs / N; % frequency
acceleration_fft_abs = abs(acceleration_fft);

end